A side airbag basically consists of a folded cushion that is quickly inflated by means of a gas produced by a generator when certain sensor devices detect a collision of the vehicle. The cushion is thus deployed between the vehicle's occupant and, usually, a door of the vehicle and protecting him/her during the collision.
In normal cushion deployment operation, the internal pressure produced by the generator when the cushion is filled with gas may be high enough to cause the cushion to be so hard that the occupant bounces off it. To prevent this drawback, they have been provided with a venting opening serving to reduce internal pressure of the cushion and, accordingly, the possibility of causing damage when they are activated.
The use of several means of blocking this venting opening to achieve a better control of the internal pressure in the cushion than that provided by only the variation of the size of the opening is in turn known. In this sense, the use of patches for achieving that the gas does not exit the discharge opening immediately but rather when the patch breaks as a given pressure inside the cushion has been reached, must be pointed out. The art has proposed different types of patches with different means for controlling the breaking thereof, more or less according to a certain resistance to the gas pressure inside the cushion. The presence of the gas pressure required for the cushion to carry out its protective function is thus made compatible with the assurance that the gas pressure will not reach an excessive value, with the risk for the people for whom the cushion is deployed.
Additionally, venting devices that allow increasing the gas outlet flow according to the specific characteristics of each collision and the type of passenger involved have also become necessary, and to that effect several venting device solutions providing surface adjustable venting openings facilitating the increase of the venting area as the internal pressure in the cushion increases are also known.
A newly arisen need involves the need for airbags that allow reducing the venting area, even completely eliminating it, in certain impact conditions, which requires closing mechanisms that must function in the sense opposite to the art known up until now. The traditional previously mentioned patches had to completely seal the outlet opening until the internal gas pressure inside the cushion did not reach a given level and then they broke, no longer functioning; now the opposite is required: devices that allow closing the venting opening in certain situations. Some proposals to that effect are known, such as the following.
Spanish patent ES 2,182,629, U.S. Pat. No. 6,139,048, US patent application 2004/0090054, patent application WO 2006/024472 and US patent application 2006/0151979 describe devices using moving elements to close the venting opening using the stresses produced in the cushion due to the pressure difference together with the difference of how the occupant strikes the airbag.
Patent applications EP 1,640,221 and WO 2007/003418 describe passive venting control mechanisms using elements which close the venting opening when certain conditions arise.
The present invention proposes a side airbag with an adaptive venting device with functionalities different from those of the mentioned art.